| 摘要 |
PROBLEM TO BE SOLVED: To provide a binarization processor capable of accurately extracting a shape without being affected by the contrast of source pictures and noise. SOLUTION: Supplied source picture data are stored in a picture memory 2 as the array of vertically (n) pieces×horizontally (m) pieces of pixels. The difference calculation means 6 of an average value obtaining means 10 calculates the difference DEF of the maximum density value and minimum density value of peripheral pixels and supplies it to a selection means 24. In the meantime, a density averaging means 20 averages the density values of the peripheral picture elements and supplies an average value AVE to the selection means 24. In a previous time average value storage means 22, the density average value AVEi ,j-1 , for a pixel, Pi ,j-1 under consideration of a previous time is stored. The selection means 24 outputs the density average value AVEi ,j-1 of the previous time as the AVEi ,j of this time when the maximum and minimum density difference DEF is smaller than an average selection threshold value and outputs the average value AVE from the density average means 20 when it is larger inversely. A binarization judgement means 12 compares the density value Ei ,j of the picture element Pi ,j , under consideration with the density average value AVE of the peripheral picture elemenet and binarizes the picture element Pi ,j under consideration.
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